Index: include/clang/Basic/Attr.td =================================================================== --- include/clang/Basic/Attr.td (revision 210052) +++ include/clang/Basic/Attr.td (working copy) @@ -1760,3 +1760,50 @@ def Unaligned : IgnoredAttr { let Spellings = [Keyword<"__unaligned">]; } + +def LoopHint : Attr { + /// vectorize: vectorizes loop operations if 'value != 0'. + /// vectorize_width: vectorize loop operations with width 'value'. + /// interleave: interleave multiple loop iterations if 'value != 0'. + /// interleave_count: interleaves 'value' loop interations. + + /// FIXME: Add Pragma spelling to tablegen and + /// use it here. + let Spellings = [Keyword<"loop">]; + + /// State of the loop optimization specified by the spelling. + let Args = [EnumArgument<"Option", "OptionType", + ["vectorize", "vectorize_width", "interleave", "interleave_count"], + ["Vectorize", "VectorizeWidth", "Interleave", "InterleaveCount"]>, + DefaultIntArgument<"Value", 1>]; + + let AdditionalMembers = [{ + static StringRef getOptionName(int Option) { + switch(Option) { + case Vectorize: return "vectorize"; + case VectorizeWidth: return "vectorize_width"; + case Interleave: return "interleave"; + case InterleaveCount: return "interleave_count"; + } + llvm_unreachable("Unhandled LoopHint option."); + } + + static StringRef getValueName(int Value) { + if (Value) + return "enable"; + return "disable"; + } + + // FIXME: Modify pretty printer to print this pragma. + void print(raw_ostream &OS, const PrintingPolicy &Policy) const { + OS << "#pragma clang loop " << getOptionName(option) << "("; + if (option == VectorizeWidth || option == InterleaveCount) + OS << value; + else + OS << getValueName(value); + OS << ")\n"; + } + }]; + + let Documentation = [Undocumented]; +} Index: include/clang/Basic/DiagnosticParseKinds.td =================================================================== --- include/clang/Basic/DiagnosticParseKinds.td (revision 210052) +++ include/clang/Basic/DiagnosticParseKinds.td (working copy) @@ -892,6 +892,10 @@ "unexpected OpenMP clause '%0' in directive '#pragma omp %1'">; def err_omp_more_one_clause : Error< "directive '#pragma omp %0' cannot contain more than one '%1' clause">; + +// Pragma loop support. +def err_pragma_loop_invalid_option : Error< + "%select{invalid|missing}0 option%select{ %1|}0; expected vectorize, vectorize_width, interleave, or interleave_count">; } // end of Parse Issue category. let CategoryName = "Modules Issue" in { Index: include/clang/Basic/DiagnosticSemaKinds.td =================================================================== --- include/clang/Basic/DiagnosticSemaKinds.td (revision 210052) +++ include/clang/Basic/DiagnosticSemaKinds.td (working copy) @@ -542,6 +542,15 @@ "#pragma visibility pop with no matching #pragma visibility push">; def note_surrounding_namespace_starts_here : Note< "surrounding namespace with visibility attribute starts here">; +def err_pragma_loop_invalid_value : Error< + "%select{invalid|missing}0 value%select{ %1|}0; expected a positive integer value">; +def err_pragma_loop_invalid_keyword : Error< + "%select{invalid|missing}0 keyword%select{ %1|}0; expected 'enable' or 'disable'">; +def err_pragma_loop_compatibility : Error< + "%select{incompatible|duplicate}0 directives '%1(%2)' and '%3(%4)'">; +def err_pragma_loop_precedes_nonloop : Error< + "expected a for, while, or do-while loop to follow the '#pragma clang loop' " + "directive">; /// Objective-C parser diagnostics def err_duplicate_class_def : Error< Index: include/clang/Basic/TokenKinds.def =================================================================== --- include/clang/Basic/TokenKinds.def (revision 210052) +++ include/clang/Basic/TokenKinds.def (working copy) @@ -701,6 +701,11 @@ ANNOTATION(pragma_openmp) ANNOTATION(pragma_openmp_end) +// Annotations for loop pragma directives #pragma clang loop ... +// The lexer produces these so that they only take effect when the parser +// handles #pragma loop ... directives. +ANNOTATION(pragma_loop_hint) + // Annotations for module import translated from #include etc. ANNOTATION(module_include) ANNOTATION(module_begin) Index: include/clang/Parse/Parser.h =================================================================== --- include/clang/Parse/Parser.h (revision 210052) +++ include/clang/Parse/Parser.h (working copy) @@ -20,6 +20,7 @@ #include "clang/Lex/CodeCompletionHandler.h" #include "clang/Lex/Preprocessor.h" #include "clang/Sema/DeclSpec.h" +#include "clang/Sema/LoopHint.h" #include "clang/Sema/Sema.h" #include "llvm/ADT/SmallVector.h" #include "llvm/Support/Compiler.h" @@ -161,6 +162,7 @@ std::unique_ptr MSCodeSeg; std::unique_ptr MSSection; std::unique_ptr OptimizeHandler; + std::unique_ptr LoopHintHandler; std::unique_ptr CommentSemaHandler; @@ -519,6 +521,10 @@ /// #pragma clang __debug captured StmtResult HandlePragmaCaptured(); + /// \brief Handle the annotation token produced for + /// #pragma vectorize... + LoopHint HandlePragmaLoopHint(); + /// GetLookAheadToken - This peeks ahead N tokens and returns that token /// without consuming any tokens. LookAhead(0) returns 'Tok', LookAhead(1) /// returns the token after Tok, etc. @@ -1601,6 +1607,9 @@ StmtResult ParseReturnStatement(); StmtResult ParseAsmStatement(bool &msAsm); StmtResult ParseMicrosoftAsmStatement(SourceLocation AsmLoc); + StmtResult ParsePragmaLoopHint(StmtVector &Stmts, bool OnlyStatement, + SourceLocation *TrailingElseLoc, + ParsedAttributesWithRange &Attrs); /// \brief Describes the behavior that should be taken for an __if_exists /// block. Index: include/clang/Sema/LoopHint.h =================================================================== --- include/clang/Sema/LoopHint.h (revision 0) +++ include/clang/Sema/LoopHint.h (working copy) @@ -0,0 +1,31 @@ +//===--- LoopHint.h - Types for LoopHint ------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_SEMA_LOOPHINT_H +#define LLVM_CLANG_SEMA_LOOPHINT_H + +#include "clang/Basic/IdentifierTable.h" +#include "clang/Basic/SourceLocation.h" +#include "clang/Sema/AttributeList.h" +#include "clang/Sema/Ownership.h" + +namespace clang { + +/// \brief Loop hint specified by a pragma loop directive. +struct LoopHint { + SourceRange Range; + Expr *ValueExpr; + IdentifierLoc *LoopLoc; + IdentifierLoc *ValueLoc; + IdentifierLoc *OptionLoc; +}; + +} // end namespace clang + +#endif // LLVM_CLANG_SEMA_LOOPHINT_H Index: lib/AST/StmtPrinter.cpp =================================================================== --- lib/AST/StmtPrinter.cpp (revision 210052) +++ lib/AST/StmtPrinter.cpp (working copy) @@ -168,8 +168,22 @@ } void StmtPrinter::VisitAttributedStmt(AttributedStmt *Node) { - for (const auto *Attr : Node->getAttrs()) - Attr->printPretty(OS, Policy); + std::string raw_attr_os; + llvm::raw_string_ostream AttrOS(raw_attr_os); + for (const auto *Attr : Node->getAttrs()) { + // FIXME: This hack will be removed when printPretty + // has been modified to print pretty pragmas + if (const LoopHintAttr *LHA = dyn_cast(Attr)) { + LHA->print(OS, Policy); + } else + Attr->printPretty(AttrOS, Policy); + } + + // Print attributes after pragmas. + StringRef AttrStr = AttrOS.str(); + if (!AttrStr.empty()) + OS << AttrStr; + PrintStmt(Node->getSubStmt(), 0); } Index: lib/CodeGen/CGStmt.cpp =================================================================== --- lib/CodeGen/CGStmt.cpp (revision 210052) +++ lib/CodeGen/CGStmt.cpp (working copy) @@ -18,6 +18,7 @@ #include "clang/AST/StmtVisitor.h" #include "clang/Basic/PrettyStackTrace.h" #include "clang/Basic/TargetInfo.h" +#include "clang/Sema/LoopHint.h" #include "clang/Sema/SemaDiagnostic.h" #include "llvm/ADT/StringExtras.h" #include "llvm/IR/CallSite.h" @@ -398,7 +399,23 @@ } void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) { - EmitStmt(S.getSubStmt()); + const Stmt *SubStmt = S.getSubStmt(); + switch (SubStmt->getStmtClass()) { + case Stmt::DoStmtClass: + EmitDoStmt(cast(*SubStmt), S.getAttrs()); + break; + case Stmt::ForStmtClass: + EmitForStmt(cast(*SubStmt), S.getAttrs()); + break; + case Stmt::WhileStmtClass: + EmitWhileStmt(cast(*SubStmt), S.getAttrs()); + break; + case Stmt::CXXForRangeStmtClass: + EmitCXXForRangeStmt(cast(*SubStmt), S.getAttrs()); + break; + default: + EmitStmt(SubStmt); + } } void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) { @@ -504,7 +521,70 @@ EmitBlock(ContBlock, true); } -void CodeGenFunction::EmitWhileStmt(const WhileStmt &S) { +void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context, + llvm::BranchInst *CondBr, + const ArrayRef &Attrs) { + // Return if there are no hints. + if (Attrs.empty()) + return; + + // Add vectorize hints to the metadata on the conditional branch. + SmallVector Metadata(1); + for (auto Attr : Attrs) { + const LoopHintAttr *LH = dyn_cast(Attr); + + // Skip non loop hint attributes + if (!LH) + continue; + + LoopHintAttr::OptionType Option = LH->getOption(); + int ValueInt = LH->getValue(); + + // FIXME: In the future I will modifiy the behavior of the metadata + // so we can enable/disable vectorization and interleaving separately. + llvm::Value *Value; + llvm::MDString *Name; + const char *MetadataNames[] = { + "llvm.vectorizer.width", "llvm.vectorizer.width", + "llvm.vectorizer.unroll", "llvm.vectorizer.unroll"}; + + switch (Option) { + case LoopHintAttr::Vectorize: + case LoopHintAttr::Interleave: + if (ValueInt == 1) { + Name = llvm::MDString::get(Context, "llvm.vectorizer.enable"); + Value = Builder.getTrue(); + break; + } + // Vectorization/interleaving is disabled, set width/count to 1. + ValueInt = 1; + // Fallthrough. + case LoopHintAttr::VectorizeWidth: + case LoopHintAttr::InterleaveCount: + Name = llvm::MDString::get(Context, MetadataNames[Option]); + Value = llvm::ConstantInt::get(Int32Ty, ValueInt); + break; + } + + SmallVector OpValues; + OpValues.push_back(Name); + OpValues.push_back(Value); + + // Set or overwrite metadata indicated by Name. + Metadata.push_back(llvm::MDNode::get(Context, OpValues)); + } + + if (!Metadata.empty()) { + // Add llvm.loop MDNode to CondBr. + llvm::MDNode *LoopID = llvm::MDNode::get(Context, Metadata); + LoopID->replaceOperandWith(0, LoopID); // First op points to itself. + + CondBr->setMetadata("llvm.loop", LoopID); + } +} + +void CodeGenFunction::EmitWhileStmt(const WhileStmt &S, + const ArrayRef &WhileAttrs) { RegionCounter Cnt = getPGORegionCounter(&S); // Emit the header for the loop, which will also become @@ -551,13 +631,17 @@ llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); if (ConditionScope.requiresCleanups()) ExitBlock = createBasicBlock("while.exit"); - Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, - PGO.createLoopWeights(S.getCond(), Cnt)); + llvm::BranchInst *CondBr = + Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, + PGO.createLoopWeights(S.getCond(), Cnt)); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); EmitBranchThroughCleanup(LoopExit); } + + // Attach metadata to loop body conditional branch. + EmitCondBrHints(LoopBody->getContext(), CondBr, WhileAttrs); } // Emit the loop body. We have to emit this in a cleanup scope @@ -588,7 +672,8 @@ SimplifyForwardingBlocks(LoopHeader.getBlock()); } -void CodeGenFunction::EmitDoStmt(const DoStmt &S) { +void CodeGenFunction::EmitDoStmt(const DoStmt &S, + const ArrayRef &DoAttrs) { JumpDest LoopExit = getJumpDestInCurrentScope("do.end"); JumpDest LoopCond = getJumpDestInCurrentScope("do.cond"); @@ -628,10 +713,15 @@ EmitBoolCondBranch = false; // As long as the condition is true, iterate the loop. - if (EmitBoolCondBranch) - Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock(), - PGO.createLoopWeights(S.getCond(), Cnt)); + if (EmitBoolCondBranch) { + llvm::BranchInst *CondBr = + Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock(), + PGO.createLoopWeights(S.getCond(), Cnt)); + // Attach metadata to loop body conditional branch. + EmitCondBrHints(LoopBody->getContext(), CondBr, DoAttrs); + } + LoopStack.pop(); // Emit the exit block. @@ -643,7 +733,8 @@ SimplifyForwardingBlocks(LoopCond.getBlock()); } -void CodeGenFunction::EmitForStmt(const ForStmt &S) { +void CodeGenFunction::EmitForStmt(const ForStmt &S, + const ArrayRef &ForAttrs) { JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); RunCleanupsScope ForScope(*this); @@ -699,9 +790,13 @@ // C99 6.8.5p2/p4: The first substatement is executed if the expression // compares unequal to 0. The condition must be a scalar type. llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); - Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, - PGO.createLoopWeights(S.getCond(), Cnt)); + llvm::BranchInst *CondBr = + Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, + PGO.createLoopWeights(S.getCond(), Cnt)); + // Attach metadata to loop body conditional branch. + EmitCondBrHints(ForBody->getContext(), CondBr, ForAttrs); + if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); EmitBranchThroughCleanup(LoopExit); @@ -743,7 +838,9 @@ EmitBlock(LoopExit.getBlock(), true); } -void CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S) { +void +CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S, + const ArrayRef &ForAttrs) { JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); RunCleanupsScope ForScope(*this); @@ -778,9 +875,12 @@ // The body is executed if the expression, contextually converted // to bool, is true. llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); - Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, - PGO.createLoopWeights(S.getCond(), Cnt)); + llvm::BranchInst *CondBr = Builder.CreateCondBr( + BoolCondVal, ForBody, ExitBlock, PGO.createLoopWeights(S.getCond(), Cnt)); + // Attach metadata to loop body conditional branch. + EmitCondBrHints(ForBody->getContext(), CondBr, ForAttrs); + if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); EmitBranchThroughCleanup(LoopExit); Index: lib/CodeGen/CodeGenFunction.h =================================================================== --- lib/CodeGen/CodeGenFunction.h (revision 210052) +++ lib/CodeGen/CodeGenFunction.h (working copy) @@ -1856,9 +1856,14 @@ void EmitGotoStmt(const GotoStmt &S); void EmitIndirectGotoStmt(const IndirectGotoStmt &S); void EmitIfStmt(const IfStmt &S); - void EmitWhileStmt(const WhileStmt &S); - void EmitDoStmt(const DoStmt &S); - void EmitForStmt(const ForStmt &S); + + void EmitCondBrHints(llvm::LLVMContext &Context, llvm::BranchInst *CondBr, + const ArrayRef &Attrs); + void EmitWhileStmt(const WhileStmt &S, + const ArrayRef &Attrs = None); + void EmitDoStmt(const DoStmt &S, const ArrayRef &Attrs = None); + void EmitForStmt(const ForStmt &S, + const ArrayRef &Attrs = None); void EmitReturnStmt(const ReturnStmt &S); void EmitDeclStmt(const DeclStmt &S); void EmitBreakStmt(const BreakStmt &S); @@ -1882,7 +1887,8 @@ void EmitCXXTryStmt(const CXXTryStmt &S); void EmitSEHTryStmt(const SEHTryStmt &S); - void EmitCXXForRangeStmt(const CXXForRangeStmt &S); + void EmitCXXForRangeStmt(const CXXForRangeStmt &S, + const ArrayRef &Attrs = None); llvm::Function *EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K); llvm::Function *GenerateCapturedStmtFunction(const CapturedDecl *CD, Index: lib/Parse/ParsePragma.cpp =================================================================== --- lib/Parse/ParsePragma.cpp (revision 210052) +++ lib/Parse/ParsePragma.cpp (working copy) @@ -15,6 +15,7 @@ #include "clang/Lex/Preprocessor.h" #include "clang/Parse/ParseDiagnostic.h" #include "clang/Parse/Parser.h" +#include "clang/Sema/LoopHint.h" #include "clang/Sema/Scope.h" #include "llvm/ADT/StringSwitch.h" using namespace clang; @@ -141,6 +142,12 @@ Sema &Actions; }; +struct PragmaLoopHintHandler : public PragmaHandler { + PragmaLoopHintHandler() : PragmaHandler("loop") {} + void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer, + Token &FirstToken) override; +}; + } // end namespace void Parser::initializePragmaHandlers() { @@ -208,6 +215,9 @@ OptimizeHandler.reset(new PragmaOptimizeHandler(Actions)); PP.AddPragmaHandler("clang", OptimizeHandler.get()); + + LoopHintHandler.reset(new PragmaLoopHintHandler()); + PP.AddPragmaHandler("clang", LoopHintHandler.get()); } void Parser::resetPragmaHandlers() { @@ -265,6 +275,9 @@ PP.RemovePragmaHandler("clang", OptimizeHandler.get()); OptimizeHandler.reset(); + + PP.RemovePragmaHandler("clang", LoopHintHandler.get()); + LoopHintHandler.reset(); } /// \brief Handle the annotation token produced for #pragma unused(...) @@ -586,6 +599,40 @@ DiagnosticsEngine::Error, "'#pragma %0' not implemented."); } +struct PragmaLoopHintInfo { + Token Loop; + Token Value; + Token Option; +}; + +LoopHint Parser::HandlePragmaLoopHint() { + assert(Tok.is(tok::annot_pragma_loop_hint)); + PragmaLoopHintInfo *Info = + static_cast(Tok.getAnnotationValue()); + + LoopHint Hint; + Hint.LoopLoc = + IdentifierLoc::create(Actions.Context, Info->Loop.getLocation(), + Info->Loop.getIdentifierInfo()); + Hint.OptionLoc = + IdentifierLoc::create(Actions.Context, Info->Option.getLocation(), + Info->Option.getIdentifierInfo()); + Hint.ValueLoc = + IdentifierLoc::create(Actions.Context, Info->Value.getLocation(), + Info->Value.getIdentifierInfo()); + Hint.Range = + SourceRange(Info->Option.getLocation(), Info->Value.getLocation()); + + // FIXME: We should support template parameters for the loop hint value. + // See bug report #19610 + if (Info->Value.is(tok::numeric_constant)) + Hint.ValueExpr = Actions.ActOnNumericConstant(Info->Value).get(); + else + Hint.ValueExpr = nullptr; + + return Hint; +} + // #pragma GCC visibility comes in two variants: // 'push' '(' [visibility] ')' // 'pop' @@ -1584,3 +1631,110 @@ Actions.ActOnPragmaOptimize(IsOn, FirstToken.getLocation()); } + +/// \brief Handle the \#pragma clang loop directive. +/// #pragma clang 'loop' loop-hints +/// +/// loop-hints: +/// loop-hint loop-hints[opt] +/// +/// loop-hint: +/// 'vectorize' '(' loop-hint-keyword ')' +/// 'interleave' '(' loop-hint-keyword ')' +/// 'vectorize_width' '(' loop-hint-value ')' +/// 'interleave_count' '(' loop-hint-value ')' +/// +/// loop-hint-keyword: +/// 'enable' +/// 'disable' +/// +/// loop-hint-value: +/// constant-expression +/// +/// Specifying vectorize(enable) or vectorize_width(_value_) instructs llvm to +/// try vectorizing the instructions of the loop it precedes. Specifying +/// interleave(enable) or interleave_count(_value_) instructs llvm to try +/// interleaving multiple iterations of the loop it precedes. The width of the +/// vector instructions is specified by vectorize_width() and the number of +/// interleaved loop iterations is specified by interleave_count(). Specifying a +/// value of 1 effectively disables vectorization/interleaving, even if it is +/// possible and profitable, and 0 is invalid. The loop vectorizer currently +/// only works on inner loops. +/// +void PragmaLoopHintHandler::HandlePragma(Preprocessor &PP, + PragmaIntroducerKind Introducer, + Token &Tok) { + Token Loop = Tok; + SmallVector TokenList; + + // Lex the optimization option and verify it is an identifier. + PP.Lex(Tok); + if (Tok.isNot(tok::identifier)) { + PP.Diag(Tok.getLocation(), diag::err_pragma_loop_invalid_option) + << /*MissingOption=*/true << ""; + return; + } + + while (Tok.is(tok::identifier)) { + Token Option = Tok; + IdentifierInfo *OptionInfo = Tok.getIdentifierInfo(); + + if (!OptionInfo->isStr("vectorize") && !OptionInfo->isStr("interleave") && + !OptionInfo->isStr("vectorize_width") && + !OptionInfo->isStr("interleave_count")) { + PP.Diag(Tok.getLocation(), diag::err_pragma_loop_invalid_option) + << /*MissingOption=*/false << OptionInfo; + return; + } + + // Read '(' + PP.Lex(Tok); + if (Tok.isNot(tok::l_paren)) { + PP.Diag(Tok.getLocation(), diag::err_expected) << tok::l_paren; + return; + } + + // FIXME: All tokens between '(' and ')' should be stored and parsed as a + // constant expression. + PP.Lex(Tok); + Token Value; + if (Tok.is(tok::identifier) || Tok.is(tok::numeric_constant)) + Value = Tok; + + // Read ')' + PP.Lex(Tok); + if (Tok.isNot(tok::r_paren)) { + PP.Diag(Tok.getLocation(), diag::err_expected) << tok::r_paren; + return; + } + + // Get next optimization option. + PP.Lex(Tok); + + auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo; + Info->Loop = Loop; + Info->Option = Option; + Info->Value = Value; + + // Generate the vectorization hint token. + Token LoopHintTok; + LoopHintTok.startToken(); + LoopHintTok.setKind(tok::annot_pragma_loop_hint); + LoopHintTok.setLocation(Loop.getLocation()); + LoopHintTok.setAnnotationValue(static_cast(Info)); + TokenList.push_back(LoopHintTok); + } + + if (Tok.isNot(tok::eod)) { + PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol) + << "clang loop"; + return; + } + + Token *TokenArray = new Token[TokenList.size()]; + std::copy(TokenList.begin(), TokenList.end(), TokenArray); + + PP.EnterTokenStream(TokenArray, TokenList.size(), + /*DisableMacroExpansion=*/false, + /*OwnsTokens=*/true); +} Index: lib/Parse/ParseStmt.cpp =================================================================== --- lib/Parse/ParseStmt.cpp (revision 210052) +++ lib/Parse/ParseStmt.cpp (working copy) @@ -15,11 +15,13 @@ #include "clang/Parse/Parser.h" #include "RAIIObjectsForParser.h" #include "clang/AST/ASTContext.h" +#include "clang/Basic/Attributes.h" #include "clang/Basic/Diagnostic.h" #include "clang/Basic/PrettyStackTrace.h" #include "clang/Basic/SourceManager.h" #include "clang/Basic/TargetInfo.h" #include "clang/Sema/DeclSpec.h" +#include "clang/Sema/LoopHint.h" #include "clang/Sema/PrettyDeclStackTrace.h" #include "clang/Sema/Scope.h" #include "clang/Sema/TypoCorrection.h" @@ -357,6 +359,10 @@ ProhibitAttributes(Attrs); HandlePragmaMSPragma(); return StmtEmpty(); + + case tok::annot_pragma_loop_hint: + ProhibitAttributes(Attrs); + return ParsePragmaLoopHint(Stmts, OnlyStatement, TrailingElseLoc, Attrs); } // If we reached this code, the statement must end in a semicolon. @@ -1759,6 +1765,37 @@ return Actions.ActOnReturnStmt(ReturnLoc, R.get(), getCurScope()); } +StmtResult Parser::ParsePragmaLoopHint(StmtVector &Stmts, bool OnlyStatement, + SourceLocation *TrailingElseLoc, + ParsedAttributesWithRange &Attrs) { + // Create temporary attribute list. + ParsedAttributesWithRange TempAttrs(AttrFactory); + + // Get vectorize hints and consume annotated token. + while (Tok.is(tok::annot_pragma_loop_hint)) { + LoopHint Hint = HandlePragmaLoopHint(); + ConsumeToken(); + + if (!Hint.LoopLoc || !Hint.OptionLoc || !Hint.ValueLoc) + continue; + + ArgsUnion ArgHints[] = {Hint.OptionLoc, Hint.ValueLoc, + ArgsUnion(Hint.ValueExpr)}; + // FIXME: Replace AS_Keyword with Pragma spelling AS_Pragma. + TempAttrs.addNew(Hint.LoopLoc->Ident, Hint.Range, 0, Hint.LoopLoc->Loc, + ArgHints, 3, AttributeList::AS_Keyword); + } + + // Get the next statement. + MaybeParseCXX11Attributes(Attrs); + + StmtResult S = ParseStatementOrDeclarationAfterAttributes( + Stmts, OnlyStatement, TrailingElseLoc, Attrs); + + Attrs.takeAllFrom(TempAttrs); + return S; +} + namespace { class ClangAsmParserCallback : public llvm::MCAsmParserSemaCallback { Parser &TheParser; Index: lib/Sema/SemaStmtAttr.cpp =================================================================== --- lib/Sema/SemaStmtAttr.cpp (revision 210052) +++ lib/Sema/SemaStmtAttr.cpp (working copy) @@ -16,6 +16,7 @@ #include "clang/Basic/SourceManager.h" #include "clang/Sema/DelayedDiagnostic.h" #include "clang/Sema/Lookup.h" +#include "clang/Sema/LoopHint.h" #include "clang/Sema/ScopeInfo.h" #include "llvm/ADT/StringExtras.h" @@ -42,7 +43,161 @@ A.getAttributeSpellingListIndex()); } +static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A, + SourceRange) { + if (St->getStmtClass() != Stmt::DoStmtClass && + St->getStmtClass() != Stmt::ForStmtClass && + St->getStmtClass() != Stmt::CXXForRangeStmtClass && + St->getStmtClass() != Stmt::WhileStmtClass) { + S.Diag(St->getLocStart(), diag::err_pragma_loop_precedes_nonloop); + return nullptr; + } + IdentifierLoc *OptionLoc = A.getArgAsIdent(0); + IdentifierInfo *OptionInfo = OptionLoc->Ident; + IdentifierLoc *ValueLoc = A.getArgAsIdent(1); + IdentifierInfo *ValueInfo = ValueLoc->Ident; + Expr *ValueExpr = A.getArgAsExpr(2); + + assert(OptionInfo && "Attribute must have valid option info."); + + LoopHintAttr::OptionType Option = LoopHintAttr::Vectorize; + if (OptionInfo->isStr("vectorize")) + Option = LoopHintAttr::Vectorize; + else if (OptionInfo->isStr("vectorize_width")) + Option = LoopHintAttr::VectorizeWidth; + else if (OptionInfo->isStr("interleave")) + Option = LoopHintAttr::Interleave; + else if (OptionInfo->isStr("interleave_count")) + Option = LoopHintAttr::InterleaveCount; + + int ValueInt; + if (Option == LoopHintAttr::Vectorize || Option == LoopHintAttr::Interleave) { + if (!ValueInfo) { + S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword) + << /*MissingKeyword=*/true << ""; + return nullptr; + } + + if (ValueInfo->isStr("disable")) + ValueInt = 0; + else if (ValueInfo->isStr("enable")) + ValueInt = 1; + else { + S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword) + << /*MissingKeyword=*/false << ValueInfo; + return nullptr; + } + } + + // FIXME: We should support template parameters for the loop hint value. + // See bug report #19610. + else if (Option == LoopHintAttr::VectorizeWidth || + Option == LoopHintAttr::InterleaveCount) { + llvm::APSInt ValueAPS; + if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context)) { + S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value) + << /*MissingValue=*/true << ""; + return nullptr; + } + + if ((ValueInt = ValueAPS.getSExtValue()) < 1) { + S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value) + << /*MissingValue=*/false << ValueInt; + return nullptr; + } + } + + return LoopHintAttr::CreateImplicit(S.Context, Option, ValueInt, + A.getRange()); +} + +static void +CheckForIncompatibleAttributes(Sema &S, SmallVectorImpl &Attrs) { + int PrevOptionValue[4] = {-1, -1, -1, -1}; + int OptionId[4] = {LoopHintAttr::Vectorize, LoopHintAttr::VectorizeWidth, + LoopHintAttr::Interleave, LoopHintAttr::InterleaveCount}; + + for (auto I = Attrs.begin(), E = Attrs.end(); I != E; ++I) { + const LoopHintAttr *LH = dyn_cast(*I); + + // Skip non loop hint attributes + if (!LH) + continue; + + int State, Value; + int Option = LH->getOption(); + int ValueInt = LH->getValue(); + + switch (Option) { + case LoopHintAttr::Vectorize: + case LoopHintAttr::VectorizeWidth: + State = 0; + Value = 1; + break; + case LoopHintAttr::Interleave: + case LoopHintAttr::InterleaveCount: + State = 2; + Value = 3; + break; + } + + SourceLocation ValueLoc = LH->getRange().getEnd(); + + // Compatibility testing is split into two cases. + // 1. if the current loop hint sets state (enable/disable) - check against + // previous state and value. + // 2. if the current loop hint sets a value - check against previous state + // and value. + + if (Option == State) { + if (PrevOptionValue[State] != -1) { + // Cannot specify state twice. + int PrevValue = PrevOptionValue[State]; + S.Diag(ValueLoc, diag::err_pragma_loop_compatibility) + << /*Duplicate=*/true << LoopHintAttr::getOptionName(Option) + << LoopHintAttr::getValueName(PrevValue) + << LoopHintAttr::getOptionName(Option) + << LoopHintAttr::getValueName(Value); + } + + if (PrevOptionValue[Value] != -1) { + // Compare state with previous width/count. + int PrevOption = OptionId[Value]; + int PrevValueInt = PrevOptionValue[Value]; + if ((ValueInt == 0 && PrevValueInt > 1) || + (ValueInt == 1 && PrevValueInt <= 1)) + S.Diag(ValueLoc, diag::err_pragma_loop_compatibility) + << /*Duplicate=*/false << LoopHintAttr::getOptionName(PrevOption) + << PrevValueInt << LoopHintAttr::getOptionName(Option) + << LoopHintAttr::getValueName(ValueInt); + } + } else { + if (PrevOptionValue[State] != -1) { + // Compare width/count value with previous state. + int PrevOption = OptionId[State]; + int PrevValueInt = PrevOptionValue[State]; + if ((ValueInt > 1 && PrevValueInt == 0) || + (ValueInt <= 1 && PrevValueInt == 1)) + S.Diag(ValueLoc, diag::err_pragma_loop_compatibility) + << /*Duplicate=*/false << LoopHintAttr::getOptionName(PrevOption) + << LoopHintAttr::getValueName(PrevValueInt) + << LoopHintAttr::getOptionName(Option) << ValueInt; + } + + if (PrevOptionValue[Value] != -1) { + // Cannot specify a width/count twice. + int PrevValueInt = PrevOptionValue[Value]; + S.Diag(ValueLoc, diag::err_pragma_loop_compatibility) + << /*Duplicate=*/true << LoopHintAttr::getOptionName(Option) + << PrevValueInt << LoopHintAttr::getOptionName(Option) << ValueInt; + } + } + + PrevOptionValue[Option] = ValueInt; + } +} + static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const AttributeList &A, SourceRange Range) { switch (A.getKind()) { @@ -53,6 +208,8 @@ return nullptr; case AttributeList::AT_FallThrough: return handleFallThroughAttr(S, St, A, Range); + case AttributeList::AT_LoopHint: + return handleLoopHintAttr(S, St, A, Range); default: // if we're here, then we parsed a known attribute, but didn't recognize // it as a statement attribute => it is declaration attribute @@ -70,6 +227,8 @@ Attrs.push_back(a); } + CheckForIncompatibleAttributes(*this, Attrs); + if (Attrs.empty()) return S; Index: test/CodeGen/pragma-loop.cpp =================================================================== --- test/CodeGen/pragma-loop.cpp (revision 0) +++ test/CodeGen/pragma-loop.cpp (working copy) @@ -0,0 +1,120 @@ +// RUN: %clang_cc1 -std=c++11 -emit-llvm -o - %s | FileCheck %s + +// Verify while loop is recognized after sequence of pragma clang loop directives. +void while_test(int *List, int Length) { + // CHECK: define {{.*}} @_Z10while_test + int i = 0; + +#pragma clang loop vectorize(enable) +#pragma clang loop interleave_count(4) +#pragma clang loop vectorize_width(4) + while (i < Length) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_1:.*]] + List[i] = i * 2; + i++; + } +} + +// Verify do loop is recognized after multi-option pragma clang loop directive. +void do_test(int *List, int Length) { + int i = 0; + +#pragma clang loop vectorize_width(8) interleave_count(4) + do { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_2:.*]] + List[i] = i * 2; + i++; + } while (i < Length); +} + +// Verify for loop is recognized after sequence of pragma clang loop directives. +void for_test(int *List, int Length) { +#pragma clang loop interleave(enable) +#pragma clang loop interleave_count(4) + for (int i = 0; i < Length; i++) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_3:.*]] + List[i] = i * 2; + } +} + +// Verify c++11 for range loop is recognized after +// sequence of pragma clang loop directives. +void for_range_test() { + double List[100]; + +#pragma clang loop vectorize_width(2) interleave_count(2) + for (int i : List) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_4:.*]] + List[i] = i; + } +} + +// Verify disable pragma clang loop directive generates correct metadata +void disable_test(int *List, int Length) { +#pragma clang loop vectorize(disable) + for (int i = 0; i < Length; i++) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_5:.*]] + List[i] = i * 2; + } +} + +#define VECWIDTH 2 +#define INTCOUNT 2 + +// Verify defines are correctly resolved in pragma clang loop directive +void for_define_test(int *List, int Length, int Value) { +#pragma clang loop vectorize_width(VECWIDTH) interleave_count(INTCOUNT) + for (int i = 0; i < Length; i++) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_6:.*]] + List[i] = i * Value; + } +} + +// Verify metadata is generated when template is used. +template +void for_template_test(A *List, int Length, A Value) { + +#pragma clang loop vectorize_width(8) interleave_count(8) + for (int i = 0; i < Length; i++) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_7:.*]] + List[i] = i * Value; + } +} + +// Verify define is resolved correctly when template is used. +template +void for_template_define_test(A *List, int Length, A Value) { +#pragma clang loop vectorize_width(VECWIDTH) interleave_count(INTCOUNT) + for (int i = 0; i < Length; i++) { + // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_8:.*]] + List[i] = i * Value; + } +} + +#undef VECWIDTH +#undef INTCOUNT + +// Use templates defined above. Test verifies metadata is generated correctly. +void template_test(double *List, int Length) { + double Value = 10; + + for_template_test(List, Length, Value); + for_template_define_test(List, Length, Value); +} + +// CHECK: ![[LOOP_1]] = metadata !{metadata ![[LOOP_1]], metadata ![[WIDTH_4:.*]], metadata ![[UNROLL_4:.*]], metadata ![[ENABLE_1:.*]]} +// CHECK: ![[WIDTH_4]] = metadata !{metadata !"llvm.vectorizer.width", i32 4} +// CHECK: ![[UNROLL_4]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 4} +// CHECK: ![[ENABLE_1]] = metadata !{metadata !"llvm.vectorizer.enable", i1 true} +// CHECK: ![[LOOP_2]] = metadata !{metadata ![[LOOP_2:.*]], metadata ![[UNROLL_4:.*]], metadata ![[WIDTH_8:.*]]} +// CHECK: ![[WIDTH_8]] = metadata !{metadata !"llvm.vectorizer.width", i32 8} +// CHECK: ![[LOOP_3]] = metadata !{metadata ![[LOOP_3]], metadata ![[UNROLL_4:.*]], metadata ![[ENABLE_1:.*]]} +// CHECK: ![[LOOP_4]] = metadata !{metadata ![[LOOP_4]], metadata ![[UNROLL_2:.*]], metadata ![[WIDTH_2:.*]]} +// CHECK: ![[UNROLL_2]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 2} +// CHECK: ![[WIDTH_2]] = metadata !{metadata !"llvm.vectorizer.width", i32 2} +// CHECK: ![[LOOP_5]] = metadata !{metadata ![[LOOP_5]], metadata ![[WIDTH_1:.*]]} +// CHECK: ![[WIDTH_1]] = metadata !{metadata !"llvm.vectorizer.width", i32 1} +// CHECK: ![[LOOP_6]] = metadata !{metadata ![[LOOP_6]], metadata ![[UNROLL_2:.*]], metadata ![[WIDTH_2:.*]]} +// CHECK: ![[LOOP_7]] = metadata !{metadata ![[LOOP_7]], metadata ![[UNROLL_8:.*]], metadata ![[WIDTH_8:.*]]} +// CHECK: ![[UNROLL_8]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 8} +// CHECK: ![[LOOP_8]] = metadata !{metadata ![[LOOP_8]], metadata ![[UNROLL_2:.*]], metadata ![[WIDTH_2:.*]]} Index: test/PCH/pragma-loop.cpp =================================================================== --- test/PCH/pragma-loop.cpp (revision 0) +++ test/PCH/pragma-loop.cpp (working copy) @@ -0,0 +1,62 @@ +// RUN: %clang_cc1 -emit-pch -o %t.a %s +// RUN: %clang_cc1 -include-pch %t.a %s -ast-print -o - | FileCheck %s + +// FIXME: A bug in ParsedAttributes causes the order of the attributes to be +// reversed. The checks are consequently in the reverse order below. + +// CHECK: #pragma clang loop interleave_count(8) +// CHECK: #pragma clang loop vectorize_width(4) +// CHECK: #pragma clang loop interleave(disable) +// CHECK: #pragma clang loop vectorize(enable) +// CHECK: #pragma clang loop interleave(enable) +// CHECK: #pragma clang loop vectorize(disable) + +#ifndef HEADER +#define HEADER + +class pragma_test { +public: + inline void run1(int *List, int Length) { + int i = 0; +#pragma clang loop vectorize_width(4) +#pragma clang loop interleave_count(8) + while (i < Length) { + List[i] = i; + i++; + } + } + + inline void run2(int *List, int Length) { + int i = 0; +#pragma clang loop vectorize(enable) +#pragma clang loop interleave(disable) + while (i - 1 < Length) { + List[i] = i; + i++; + } + } + + inline void run3(int *List, int Length) { + int i = 0; +#pragma clang loop vectorize(disable) +#pragma clang loop interleave(enable) + while (i - 3 < Length) { + List[i] = i; + i++; + } + } +}; + +#else + +void test() { + int List[100]; + + pragma_test pt; + + pt.run1(List, 100); + pt.run2(List, 100); + pt.run3(List, 100); +} + +#endif Index: test/Parser/pragma-loop-ast.cpp =================================================================== --- test/Parser/pragma-loop-ast.cpp (revision 0) +++ test/Parser/pragma-loop-ast.cpp (working copy) @@ -0,0 +1,35 @@ +// RUN: %clang_cc1 -ast-print %s | FileCheck %s + +// FIXME: A bug in ParsedAttributes causes the order of the attributes to be +// reversed. The checks are consequently in the reverse order below. + +// CHECK: #pragma clang loop interleave_count(8) +// CHECK: #pragma clang loop vectorize_width(4) +// CHECK: #pragma clang loop interleave(disable) +// CHECK: #pragma clang loop vectorize(enable) +// CHECK: #pragma clang loop interleave(enable) +// CHECK: #pragma clang loop vectorize(disable) + +void test(int *List, int Length) { + int i = 0; +#pragma clang loop vectorize_width(4) +#pragma clang loop interleave_count(8) + while (i < Length) { + List[i] = i * 2; + i++; + } + +#pragma clang loop vectorize(enable) +#pragma clang loop interleave(disable) + while (i - 1 < Length) { + List[i] = i * 2; + i++; + } + +#pragma clang loop vectorize(disable) +#pragma clang loop interleave(enable) + while (i - 2 < Length) { + List[i] = i * 2; + i++; + } +} Index: test/Parser/pragma-loop.cpp =================================================================== --- test/Parser/pragma-loop.cpp (revision 0) +++ test/Parser/pragma-loop.cpp (working copy) @@ -0,0 +1,132 @@ +// RUN: %clang_cc1 -std=c++11 -verify %s + +// Note that this puts the expected lines before the directives to work around +// limitations in the -verify mode. + +void test(int *List, int Length) { + int i = 0; + +#pragma clang loop vectorize(enable) +#pragma clang loop interleave(enable) + while (i + 1 < Length) { + List[i] = i; + } + +#pragma clang loop vectorize_width(4) +#pragma clang loop interleave_count(8) + while (i < Length) { + List[i] = i; + } + +#pragma clang loop vectorize(disable) +#pragma clang loop interleave(disable) + while (i - 1 < Length) { + List[i] = i; + } + +#pragma clang loop vectorize_width(4) interleave_count(8) + while (i - 2 < Length) { + List[i] = i; + } + +#pragma clang loop interleave_count(16) + while (i - 3 < Length) { + List[i] = i; + } + + int VList[Length]; +#pragma clang loop vectorize(disable) interleave(disable) + for (int j : VList) { + VList[j] = List[j]; + } + +/* expected-error {{expected '('}} */ #pragma clang loop vectorize +/* expected-error {{expected '('}} */ #pragma clang loop interleave + +/* expected-error {{expected ')'}} */ #pragma clang loop vectorize(enable +/* expected-error {{expected ')'}} */ #pragma clang loop interleave(enable + +/* expected-error {{expected ')'}} */ #pragma clang loop vectorize_width(4 +/* expected-error {{expected ')'}} */ #pragma clang loop interleave_count(4 + +/* expected-error {{missing option}} */ #pragma clang loop +/* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop badkeyword +/* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop badkeyword(enable) +/* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop vectorize(enable) badkeyword(4) +/* expected-warning {{extra tokens at end of '#pragma clang loop'}} */ #pragma clang loop vectorize(enable) , + + while (i-4 < Length) { + List[i] = i; + } + +/* expected-error {{invalid value 0; expected a positive integer value}} */ #pragma clang loop vectorize_width(0) +/* expected-error {{invalid value 0; expected a positive integer value}} */ #pragma clang loop interleave_count(0) + while (i-5 < Length) { + List[i] = i; + } + +/* expected-error {{invalid value -1294967296; expected a positive integer value}} */ #pragma clang loop vectorize_width(3000000000) +/* expected-error {{invalid value -1294967296; expected a positive integer value}} */ #pragma clang loop interleave_count(3000000000) + while (i-6 < Length) { + List[i] = i; + } + +/* expected-error {{missing value; expected a positive integer value}} */ #pragma clang loop vectorize_width(badvalue) +/* expected-error {{missing value; expected a positive integer value}} */ #pragma clang loop interleave_count(badvalue) + while (i-6 < Length) { + List[i] = i; + } + +/* expected-error {{invalid keyword 'badidentifier'; expected 'enable' or 'disable'}} */ #pragma clang loop vectorize(badidentifier) +/* expected-error {{invalid keyword 'badidentifier'; expected 'enable' or 'disable'}} */ #pragma clang loop interleave(badidentifier) + while (i-7 < Length) { + List[i] = i; + } + +#pragma clang loop vectorize(enable) +/* expected-error {{expected a for, while, or do-while loop to follow the '#pragma clang loop' directive}} */ int j = Length; + List[0] = List[1]; + + while (j-1 < Length) { + List[j] = j; + } + +// FIXME: A bug in ParsedAttributes causes the order of the attributes to be +// processed in reverse. Consequently, the errors occur on the first of pragma +// of the next three tests rather than the last, and the order of the kinds +// is also reversed. + +/* expected-error {{incompatible directives 'vectorize(disable)' and 'vectorize_width(4)'}} */ #pragma clang loop vectorize_width(4) +#pragma clang loop vectorize(disable) +/* expected-error {{incompatible directives 'interleave(disable)' and 'interleave_count(4)'}} */ #pragma clang loop interleave_count(4) +#pragma clang loop interleave(disable) + while (i-8 < Length) { + List[i] = i; + } + +/* expected-error {{duplicate directives 'vectorize(disable)' and 'vectorize(enable)'}} */ #pragma clang loop vectorize(enable) +#pragma clang loop vectorize(disable) +/* expected-error {{duplicate directives 'interleave(disable)' and 'interleave(enable)'}} */ #pragma clang loop interleave(enable) +#pragma clang loop interleave(disable) + while (i-9 < Length) { + List[i] = i; + } + +/* expected-error {{incompatible directives 'vectorize_width(4)' and 'vectorize(disable)'}} */ #pragma clang loop vectorize(disable) +#pragma clang loop vectorize_width(4) +/* expected-error {{incompatible directives 'interleave_count(4)' and 'interleave(disable)'}} */ #pragma clang loop interleave(disable) +#pragma clang loop interleave_count(4) + while (i-10 < Length) { + List[i] = i; + } + +/* expected-error {{duplicate directives 'vectorize_width(4)' and 'vectorize_width(8)'}} */ #pragma clang loop vectorize_width(8) +#pragma clang loop vectorize_width(4) +/* expected-error {{duplicate directives 'interleave_count(4)' and 'interleave_count(8)'}} */ #pragma clang loop interleave_count(8) +#pragma clang loop interleave_count(4) + while (i-11 < Length) { + List[i] = i; + } + +#pragma clang loop interleave(enable) +/* expected-error {{expected statement}} */ }